One vertex per element, one color per generator, with an edge from x to x·s.
(5,6,8,9)(7,10,11,12)(13,14,17,23,18,21,16,22)(15,24,26,19,27,28,25,20)(1,2)(3,4)(6,9)(10,12)(13,15)(14,19)(16,26)(17,25)(18,27)(20,21)(22,28)(23,24) involution — undirected(2,4)(13,15)(14,20)(16,26)(17,25)(18,27)(19,21)(22,24)(23,28) involution — undirected(5,7,8,11)(6,10,9,12)(14,21)(16,17)(19,20)(25,26)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.